Acetaminophen is a well-known analgesic and antipyretic which reduces the discomfort and fever due to colds and other viral infections.
Pseudoephedrine and pharmaceutically acceptable salts thereof, e.g. the sulfate and the hydrochloride, are well-known decongestants which restore freer breathing by shrinking nasal passages and promote sinus drainage in those suffering from colds, allergies or sinusitis.
Dexbrompheniramine and pharmaceutically acceptable salts thereof, e.g. the maleate, are well-known antihistamines which provide relief of the pruritis, rhinitis and sneezing associated with colds and allergies.
Controlled-release dosage forms which comprise a single active component are well known, including matrix tablet systems incorporating active ingredients, lubricants, binders, fillers and other excipients, wherein the binders may be hydrophilic, hydrophobic or water-insoluble polymers; see for example U.S. Pat. No. 4,389,393. However, controlled-release dosage forms which combine two actives are not common, and but for U.S. Pat. No. 4,601,894 and U.S. Pat. No. 4,657,757, wherein hydroxypropyl methylcellulose must be present as a binder, no controlled-release dosage forms combining three actives in a single uniform dosage form are known because of the difficulties encountered in combining multiple actives, each with different chemical and physical characteristics, different release rates, different half-lives and different dosage sizes.
The mechanism by which controlled-release dosage forms act to dispense the active ingredients over a period of time have been described at length in the literature; see for example Manford Robinson, Chapter 14, "Sustained Action Dosage Forms", The Theory and Practice of Industrial Pharmacy, 2nd. ed., ed. L. Lachman, H. Lieberman and J. Kanig (Philadelphia; Lea & Febiger, 1976).